#define _CRT_SECURE_NO_WARNINGS

#include<iostream>
#include<vector>
using namespace std;

class Solution {
public:
    int singleNumber(vector<int>& nums) {
        int ret = 0;
        for (int i = 0; i < 32; i++)
        {
            int sum = 0;
            for (auto x : nums)
                if (((x >> i) & 1) == 1) ++sum;
            sum %= 3;
            if (sum == 1)
                ret |= (1 << i);
        }
        return ret;
    }


};